Present: Peter Bosted, Keith Griffioen, Piotr Decowski,
Bill Olson, Perry Anthony, Steve Rock, Don Crabb
E160 Target: LiD rod good idea (DOn has 6, 1 cm by 10 cm) as a low Z target
Dieter should do some heat calculations to decide between lead, Au, etc.
Should we use gold or lead? Decide 0.12 r.l. target would be
better than 0.2 r.l. Can get more photon beam intenisty, only
question is will quantameter take it?
E161 Target: Steve asks about using Li as a background target. Don says
may be able to change unpol. targets more quickly than pol. ones. Use Be
windows on pol. target? Need to really minimize r.l. of unpolarized
material in E161 target.
Detector size: small ones covering good resol. area may be
prefered, because backgrounds also increase with area, and this limits
useable luminosity. Concensus is to use smalller detectors (pending
looking at Pitor's new outputs).
Piotr looked at desired thickness: thicker detectors give more sprinkle
hits, but less than linear, and average energy doesn't increase much.
So thicker detectors allow higher threshold, less sprinkle hits above
thrshold. Shorter detectors better since attenuation effects cause
less spread in muon signal size.
Peter talked about "box tie" design that minimizes BH muons. Would
like a set of small detectors specifically to measure low angle
BH muons for crytal calibration and luminosity monitoring, esp. if
Compton Pol. not ready for E160.
Internal Design Review. Now looking at July 9 or 10 for this, to
match people's schedules. Will prepare budget for S. Williams to
be submitted July 16. External design review postponed until
mid-August (around time of next Coll. meeting).